EP0674150B1 - Ammunition with anti-wear additives - Google Patents

Description

The field of the present invention is that of ammunition intended to be fired by a tube weapon and which include a propellant charge and a projectile carrying a propulsion gas tightness belt.

Whatever their caliber, these munitions cause significant wear to the gun barrel.

It is known to provide anti-wear additives mixed with the propellant charge contained in the case or deposited on the inner wall of the latter. So the patent US3148620 describes various compositions, in particular based on titanium dioxide and wax, arranged inside the propellant charge.

The disadvantage of such solutions is that the extra set up has little effect on the ammunition fired but is rather useful for ammunition fired later.

Indeed the ammunition engages the tube by its belt at points which will not be covered by the backup until after the passage of the projectile. The wear caused by the latter therefore remains relatively important.

In addition it is difficult to control the distribution extra in the tube since, on the one hand it is thrown by hot gases in a random way and other apart the distribution of the extra in the case can in some cases change and become asymmetrical during the ammunition storage (by the action of temperature and vibrations).

We know, in particular by patents FR672702 and FR825752, projectiles which include an anti-wear back-up fixed on their external wall by means of an envelope or still placed in housings of the projectile body.

Such provisions require the implementation of complex fixing means or carrying out machining expensive on the projectile body which can also affect its terminal efficiency.

The anti-wear back-up implementation is made even more necessary by the development of ammunition telescoped.

In a known way (for example by patent FR2647891) these munitions have a case inside which houses the projectile entirely.

This results in equal performance dimensions reduced for ammunition, which allows the development compact weapons.

The increase in performance allowed by telescoped ammunition leads to implementing a backup anti-wear.

But the compactness of these munitions limits the volume available in the case and makes it even more complex in place of such a backup.

Patent US4715284, the description of which is taken from the preamble of claim 1, describes a telescoped munition in which an annular anti-wear backing layer is deposited on the propellant charge, in front of the projectile.

This brings with it part of the extra during the firing, the rest of the make-up being distributed by the gas pressure.

Such a concept has drawbacks.

First of all the installation of the backup is a complex operation of deposition on a reactive material (the propellant charge), deposit which can only be made after mounting the projectile.

Then the back-up distribution mechanism combines the mechanical action of the projectile and that of the gases propellants, with the disadvantages of this last in terms of distribution (drawbacks cited above).

Finally, the anti-wear supplement being deposited on the propellant charge, there is a risk of chemical combination between these two elements, leading to a loss of top-up and load efficiency after long storage periods.

It is the object of the invention to propose a ammunition (especially telescoped) to overcome such disadvantages.

The invention thus provides ammunition, in particular telescoped, which carry an anti-wear supplement which is place in the case in a simple and inexpensive way.

The back-up maintenance means ensure nevertheless a conservation of it during the phases of ammunition storage and ensure the stability of the distribution of the extra on the barrel even after extended storage phases.

The invention also provides ammunition (telescoped or not) whose anti-wear back-up has a superior protective efficiency with respect to the weapon.

Indeed, these ammunition allow to distribute reliable and regular anti-wear back-up throughout of the barrel of the weapon, since the auxiliary is distributed by the projectile itself and not by the propellant charge.

The ammunition according to the invention also makes it possible to distribute the anti-wear back-up reliably and regularly in front of the projectile, at points that have not yet been reached by the belt.

The backup therefore exerts its protective action directly opposite the projectile which is fired.

According to a variant, the ammunition according to the invention can carry additions of different nature arranged in different reception areas which further increases the effectiveness of the protection provided. This variant is not not limited to telescoped ammunition.

Thus, the subject of the invention is an ammunition comprising a case containing a propellant charge and a projectile, having a body and a belt for sealing against propellant gases, the projectile being telescoped inside the case and held by a cap. integral with the latter and fitted in a front ring closing the case, an anti-wear supplement driven by the projectile being disposed in front of the latter during firing, characterized in that the anti-wear supplement is disposed at the level of at least one receiving area carried by the cap and is therefore driven by the projectile when fired.

The cap will advantageously present an area annular in which are arranged at least two bores parallel to the axis of the ammunition and regularly distributed angularly, the bores communicating with a surface external cylindrical of the cap by holes and the addition anti-wear is placed in the bores.

According to another embodiment of the invention in which the projectile has an under-calibrated bar placed in a caliber shoe, the anti-wear back-up is arranged at at least one reception area which includes a front pocket on the hoof, the topping up therefore finding itself driven by the projectile during the firing.

According to another embodiment of the invention in which the projectile has an under-calibrated bar placed in a caliber shoe, the anti-wear back-up is arranged at at least one reception area which includes at least one peripheral housing on the shoe in front of the belt, the extra is therefore driven by the projectile when fired.

According to another embodiment of the invention in which the case is closed by a plug formed by a front ring sealed with a seal, the anti-wear back-up is arranged at at least one reception area which includes the cover, the topping up therefore finding itself driven by the projectile during the firing.

According to another embodiment, of the invention an anti-wear additive front layer is deposited on minus a reception area which is the very body of the projectile in front of the belt.

According to another embodiment, a layer anti-wear backing pad is deposited on at least one receiving area which is the very body of the projectile in back of the belt.

According to a variant of the invention, the ammunition includes a case containing a propellant charge and a projectile, having a body and a sealing belt with propellant gases, this ammunition is characterized in that that it has at least two reception areas with a anti-wear back-up, areas secured to the projectile or likely to be dragged by him during the shooting, the materials constituting the anti-wear additives deposited in each of the two reception areas being of a nature different.

Such an alternative embodiment is not limited to an application on telescoped ammunition.

Advantageously, a reception area is located front of the belt and the other behind the belt.

Preferably, the material or materials arranged in front of the belt are compositions for reduce friction and / or wear and the material (s) arranged behind the belt are compositions reducing the erosive effects of hot gases.

Such an arrangement makes it possible to obtain an efficiency the action of the anti-wear additives.

• la figure 1a représente en coupe axiale une munition télescopée selon un premier mode de réalisation de l'invention,
• la figure 1b est une coupe suivant le plan AA de la figure 1a,
• la figure 2 représente en coupe axiale une munition télescopée selon un deuxième mode de réalisation de l'invention,
• la figure 3 représente en coupe axiale une munition télescopée selon un troisième mode de réalisation de l'invention.

Other advantages of the invention will appear on reading the description which follows of different embodiments, description made with reference to the appended drawings and in which:

• FIG. 1a represents in axial section a telescoped munition according to a first embodiment of the invention,
• FIG. 1b is a section along the plane AA of FIG. 1a,
• FIG. 2 shows in axial section a telescoped munition according to a second embodiment of the invention,
• Figure 3 shows in axial section a telescoped munition according to a third embodiment of the invention.

If we refer to Figures 1a and 1b, ammunition telescoped 1 according to a first embodiment of the invention comprises a case 2, made for example in plastic, and closed at its rear end by a plug 3 and at its front end by a ring 4.

The case contains a non-propellant powder represented.

The rear plug 3 is formed by a reinforcing plate metal 5 to which a lip is fixed by clipping seal 6 made of plastic. The rear plug 3 carries a known type igniter 7.

The front ring 4 has a tubular reinforcement metal 8 to which a lip is fixed by clipping seal 9 made of plastic.

A 10 caliber projectile carries at its rear a belt 11 fixed by crimping in a groove 12.

The projectile carries at its warhead 13 a cap 14, made of plastic or composite, and which has an internal profile 15 corresponding to the profile outside of the warhead 13.

The cap 14 has an internal cylindrical bore 37, it is fixed to the projectile by gluing (it could also be snap-fastened).

It is tightly adjusted in the bore cylindrical 16 of the front ring 4.

Such a cap is described in detail in the patent FR8907231. Its function is to maintain the projectile relative to the case of the ammunition and sealing the load combustion gases propellant.

The cap is intended to fragment at the exit of the barrel of the weapon by the action of centrifugal forces which exercise on it. It includes an annular portion 16 in which blind bores 17 are arranged, parallel to the axis 18 of the ammunition, which weaken the cap and facilitate breakage.

Bores 17 are regularly distributed angularly, they communicate by holes 20 with a external cylindrical surface 19 of the cap 14.

When the projectile is positioned in the holster, the holes 20 are closed in a simple way by the surface internal cylindrical of the tubular reinforcement 8 of the front ring 4.

Bores 17 constitute a reception area for an anti-wear supplement 26 constituted for example by a mixture of titanium dioxide and wax which is placed in the bores 17.

The top-up may include an anti-wear material associated with a binder with a relative proportion of 30 to 50% of binder.

We can choose as anti-wear material the Tungsten trioxide, talc or titanium dioxide, and like binding wax.

We can also use a grease.

A plastic cover 21 is fixed by example by gluing on a counterbore 22 arranged on the face front of ring 4.

The projectile 10 also carries a front layer 23 anti-wear supplement placed on a reception area of the body of the projectile itself and in front of the belt 11.

The projectile 10 also carries a rear layer 24 anti-wear pad deposited behind the belt at level of a conical receiving zone 25.

These two layers can also be formed of a mixture of wax and titanium dioxide or be formed by depositing another type of material.

The material of the front and rear make-up layers anti-wear will be put in place by casting after fusion and in rotating the projectile to distribute the support regularly.

In order to improve the attachment of the make-up to the body of the projectile we will give the surface of it a sufficient roughness (by machining or attack by an acid).

When firing the ammunition, the projectile 10 carrying its cap 14 is pushed into the barrel of the weapon. The displacement of the cap causes the clearance of the holes 20.

Anti-wear supplement 26, driven by efforts of longitudinal and centrifugal inertia, can then exit by the holes and settle in the tube. Maximum deposit booster is performed at the tube where the acceleration of rotation is maximum, most often in the second half the length of the tube.

Following the advancement of the projectile in the tube the weapon, the additional front layer 23 is deposited on the beginning of the scratches and before they are engaged by the belt.

The belt 11 then engages the tube already covered with protective material.

Throughout the course of the projectile in the tube of the weapon an anti-wear back-up will therefore be put in place successively or jointly by the front layer 23 and by the cap 14.

The invention therefore provides an effect protector against the action of the projectile which is fired.

In addition, the invention makes it possible to provide an action protective at the two points most sensitive to wear: the beginning of scratching where the belt engages and the maximum rotation acceleration point.

The start of scratching is protected by the back-up from the front layer 23.

The maximum rotation acceleration point is protected by the extra 26 deposited by the cap.

The rear booster layer 24 disposed behind the belt 11 completes the protective deposit before firing of the following munitions. Tying this layer to projectile ensures a distribution of the material while along the tube.

Due to its placement in holes regularly distributed angularly, the extra 26 will keep even distribution in the case throughout ammunition storage.

Alternatively, it is possible to provide different materials for the extra contained in the cap, the one in the front layer and the one in the layer back.

• comme matériau déposé par la coiffe une composition permettant de diminuer le frottement (telle une graisse),
• comme matériau pour la couche avant une composition pour diminuer le frottement (telle une graisse) ou une composition anti-usure/anti-frottement comme le talc associé à la cire,
• comme matériau pour la couche arrière un appoint anti-usure classique permettant de diminuer les effets érosifs des gaz propulsifs chauds (comme le dioxyde de titane ou le trioxyde de tungstène associés à la cire).

We could for example use:

• as material deposited by the cap, a composition making it possible to reduce friction (such as a grease),
• as a material for the layer before a composition for reducing friction (such as a grease) or an anti-wear / anti-friction composition such as talc associated with wax,
• as a material for the rear layer, a conventional anti-wear supplement making it possible to reduce the erosive effects of hot propellant gases (such as titanium dioxide or tungsten trioxide associated with the wax).

It is also possible to provide only the material contained in the cap or that of the layer before or even only that of the rear layer.

As a variant it is possible to have in the internal bore 37 of the cap 14 (in addition to or at the place of material 26 of bores 17) anti-wear material such as fat, whether or not placed in a plastic bag.

FIG. 2 represents a telescoped munition of which the case 2 is closed at its rear part by a plug 3 and at its front part by another plug formed by a ring 4. The projectile 10 comprises a sub-calibrated bar 32 disposed in a shoe of caliber 33.

The under-calibrated bar carries a tail unit 27 at its rear part. The belt 11 is in abutment against the ring front 4. The projectile is held axially and radially with respect to the case by holding means which may include a rear wedge 28 and an engaged elastic ring in the front ring (not shown here).

The patents FR2647891 and FR2679991 describe in detail of such holding means.

Shoe 33 of the projectile carries an anti-wear back-up 26 deposited in a front pocket 29 which thus constitutes a reception area for back-up. The backup is in place by casting. A protective glitter can be put in place after depositing the extra in the pocket to ensure its symmetrical layer maintenance during the phases of storage.

The shoe also has a rear layer 24 anti-wear supplement placed on a reception area outer shoe behind the belt.

The front ring 4 is closed by a seal 21 glued at a counterbore 22. The cover carries an extension cylindrical 30 having an internal housing 31 which constitutes a reception area for anti-wear back-up 26.

A closing straw can be put in place after depositing the extra to ensure its maintenance in the lid in a symmetrical layer.

The cover is broken by the projectile during the firing of the ammunition, and the add-on 26 it contains found distributed in the tube at the front of the projectile and driven by it.

The back-ups arranged in the cover and in the front hoof pocket will spread throughout the course of the projectile in the tube. Adding the seal is will spread especially from the start of the tube and it plays the role of the addition of the front layer described above in reference to Figure 1 (it may consist of grease or a talc / wax mixture).

The extra pocket 29 will fall into place more gradually along the tube and maximum in the second half of it when the shot is made with a striped tube. It plays the role of the added headdress described previously and will preferably consist of fat.

The addition of the rear layer may include titanium dioxide, tungsten trioxide or talc.

Figure 3 also shows a telescoped munition whose case 2 is closed at its rear part by a plug 3 and at its front part by a ring 4 closed by a cover 21 made of plastic.

Projectile 10 includes an under-calibrated bar 32 placed in a shoe 33 to the caliber. The projectile is here gyrostabilized and the shoe has a bottom 33a produced by example in steel and on which a shirt 33b is molded made of plastic.

Slots (not shown) are provided between the bottom and shirt. We could for example refer to patent FR2653873 which describes such a projectile.

The belt 11 bears against the front ring 4, guidance of the projectile in the ring is also ensured by cylindrical spans 34 and 35. A peripheral groove 36 is arranged on the shirt 33b of the shoe 33 in front of the belt 11.

This groove is delimited by the ranges 34 and 35, it is intended to lighten the hoof and facilitate its burst at the exit of the barrel of the weapon. It constitutes a reception area for anti-wear back-up 26.

After mounting the projectile in the front ring 4, the anti-wear back-up is maintained by the surface inner cylindrical of the ring and it retains a even distribution in the case during storage of ammunition.

The extra deposited in the throat plays the role of the addition of the front layer described previously with reference in Figure 1 (it may consist of grease or a talc / wax mixture). This supplement spreads in particular from beginning of the tube and before engagement of the belt.

The shoe 33 of the projectile also carries a booster anti-wear 26 deposited in a reception area which is a front pocket 29. This backup plays the role of the backup cap described above with reference to Figure 1. It is gradually spread along the tube and as much as possible in the second half of it following efforts developed centrifuges (it will preferably consist of fat).

The shoe finally carries an additional rear layer 24 anti-wear deposited on a conical bottom receiving area 33a of the hoof behind the belt. This supplement may contain titanium dioxide, tungsten trioxide or talc. It reduces the erosive effects of hot gases.

As a variant it is possible to replace the groove 36 by several housings arranged radially in the shirt 33b and regularly distributed angularly (see par example the housings described in patent FR2653873).

It is of course possible to combine the different embodiments described above and in particular to use a cover of the type of that shown Figure 2 in the ammunition shown in Figures 1 and 3.

The embodiment of Figure 3 can also be implemented with a non-telescoped projectile.

In this case the case will be crimped on a throat of the projectile disposed behind the belt. The projectile will wear a rear layer 24 of an anti-wear supplement reducing the erosive effects of gases (titanium dioxide or tungsten trioxide associated with wax). He will wear also in the peripheral groove 36 (in front of the belt) anti-wear and / or anti-friction support as talc associated with wax. This supplement will be widespread in the weapon barrel from the start of the barrel and before engagement of the belt.

The projectile can finally carry an anti-wear booster 26 deposited in the front pocket 29. This make-up will be a friction-reducing material (such as grease), and apart from its arrangement in pocket 29, it will be distributed maximum in the second half of the tube.

Due to the non-telescoped nature of the ammunition, the back-ups arranged in the groove 36 and / or in the pocket 29 will be protected by glitter.

Claims (10)

1. A piece of ammunition (1) incorporating a casing (2) containing a propellant charge and a projectile (10), having a body and band to seal (11) against the propellant gases, the projectile being telescoped inside the casing and held in place by a nose cone (14) integral with said casing and fitted into a front ring (4) closing off the casing, an anti-wear additive drawn by the projectile being deposited to the fore of said projectile during firing, characterised in that the anti-wear additive (26) is deposited in at least one reception area carried by the nose cone (14) and is therefore drawn by the projectile during firing.
2. A piece of ammunition according to Claim 1, characterised in that the nose cone (14) has a ring-shaped area in which at least two bores(17) are arranged in parallel to the munition axis and evenly distributed angularly, said bores communicating with an external cylindrical surface of the nose cone (14) by holes (20) and in that the anti-wear additive (26) is placed in said bore holes (17).
3. A piece of ammunition (1) according to Claim 1 and in which the projectile has a sub-calibred penetrator (32) arranged in a calibred sabot (33), characterised in that the anti-wear additive (26) is deposited in at least one reception area that comprises a front pocket (29) arranged on the sabot (33), the additive being thus drawn by the projectile during firing.
4. A piece of ammunition (1) according to Claim 1 and in which the projectile incorporates a sub-calibred penetrator (32) arranged in a calibred sabot (33), characterised in that the anti-wear additive (26) is deposited in at least one reception area which comprises at least one peripheral housing (36) arranged on the sabot to the fore of the band (11), the additive is thus drawn by the projectile during firing.
5. A piece of ammunition (1) according to Claim 1 and in which the casing is closed by a plug formed by a front ring (4) obturated in a gastight manner by a cap (21), the anti-wear additive (26) is deposited in at least one reception area that comprises the cap (21), the additive is thus drawn by the projectile during firing.
6. A piece of ammunition according to one of Claims 1 to 5, characterised in that a front layer (23) of anti-wear additive is deposited on at least one reception area which is the body of the projectile (10) itself to the fore of the band (11).
7. A piece of ammunition according to one of Claims 1 to 6, characterised in that a rear layer (24) of anti-wear additive is deposited on at least one reception area which is the body of the projectile (10) itself to the rear of the band (11).
8. A piece of ammunition (1) incorporating a casing (2) containing a propellant charge and a projectile (10), having a body and sealing band (11) for the propellant gases, characterised in that it incorporates at least two reception areas carrying an anti-wear additive, areas integral with the projectile (10) or likely to be drawn by it during firing, the materials forming the anti-wear additives deposited in each of the two reception areas being of a different nature.
9. A piece of ammunition according to Claim 8, characterised in that a reception area is located to the fore of the band and the other to the rear of the band.
10. A piece of ammunition according to Claim 9, characterised in that the material or materials deposited to the fore of the band are components enabling the friction and/or wear to be reduced and the material or materials deposited to the rear of the band are compositions to reduce the erosive effects of the hot gases.

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